The 1.25Acrystal structure of sepiapterin reductase reveals its binding mode to pterins and brain neurotransmitters
作者:G. Auerbach
DOI:10.1093/emboj/16.24.7219
日期:1997.12.15
Ternary complexes with the substrate sepiapterin or the product tetrahydrobiopterin were studied. Each subunit contains a specific aspartate anchor (Asp258) for pterin-substrates, which positions the substrate side chain C1'-carbonyl group near Tyr171 OH and NADP C4'N. The catalytic mechanism of SR appears to consist of a NADPH-dependent proton transfer from Tyr171 to the substrate C1' and C2' carbonyl functions
Sepaapterin还原酶催化生物合成四氢生物蝶呤的最后一步,这是芳香族氨基酸羟化酶和一氧化氮合酶的必要辅助因子。我们已经通过以1.25 A的分辨率与草酰乙酸和NADP形成三元复合物,通过多次同构置换确定了小鼠Sepaapterin还原酶的晶体结构。同型二聚体结构揭示了一个单结构域的alpha / beta折叠,带有一个中央的四螺旋束,该束连接了两个七链平行的β-折叠,每个折叠都夹在三个三个螺旋的两个阵列之间。研究了具有底物Sepaapterin或四氢生物蝶呤产物的三元复合物。每个亚基均包含用于蝶呤底物的特定天冬氨酸锚定(Asp258),该底物锚定底物侧链C1'-羰基位于Tyr171 OH和NADP C4'N附近。SR的催化机制似乎由从Tyr171到底物C1'和C2'羰基官能团的NADPH依赖的质子转移以及伴随的立体特异性侧链异构化组成。与抑制剂N-乙酰基5-羟色胺形成的复杂结构显示吲哚